Drill steel centralizers



Jan. 25, 1966 s, YTTERFORS DRILL STEEL CENTRALIZERS 2 Sheets-Sheet 1 Filed June 12, 1962 Fig.3

Fig.2

77 W Amme v Jan. 25, 1966 s. L. YTTERFORS DRILL STEEL CENTRALIZERS 2 Sheets-Sheet 2 Filed June 12, 1962 INVENTOR. @ENLAMQENTlU-S Y7TERPOE Am G NET United States Patent 3,231,318 DRILL STEEL CENTRALTZERS Sven Lanrentius Ytterfors, Naclra, Sweden, assignon to Atlas Copco Airtieholag, Nacira, Sweden, a corporation of Sweden Filed June 12, 1962, Ser. No. 201,977 10 Claims. (Cl. 308-3.?)

This invention relates to rock drills and more particularly to an improved drill steel centralizer or guide of the type intended to provide a rigid support for the free end of the drill steel when starting a hole on an irregular work surface.

A primary object of the invention is to provide a rigid and very simple drill steel centralizer intended to be operated by power and remotely controlled. Another object of the invention is to provide a power operated drill steel centralizer in which the application of power on the guiding jaws of the centralizer is as direct as possible. A further object of the invention is to provide a power operated drill steel centralizer which additionally to the guiding task is able to perform a powerful gripping of the drill steel equipment in vise-like manner. A still further object of the invention is to provide a pressure fluid operted drill steel centralizer in which the guiding jaws are directly connected to one of the elements of the power cylinder and piston means used for application of the fluid power, without the use of interposed power transmitting means such as pivoted links, arms and the like.

The above and other objects of the invention will become obvious from the following description and from the accompanying drawings in which an embodiment of the invention is illustrated by way of example. It should be understood that this embodiment is only illustrative of the invention and that various modifications may be made within the scope of the claims without departing from the scope of the invention.

In the drawings, FIG. 1 shows a side view partly in section of a centralizer according to the invention and viewed substantially on lines 11 in FIG. 2. FIG. 2 is a rear view of the centralizer in FIG. 1 with the guiding jaws closed for guiding a drill rod. FIG. 3 shows extension drill steel members joined together into a fragmentarily illustrated drill steel for long hole drilling and intended for use together with the drill steel centralizer according to the invention. FIG. 4 is an enlarged fragmentary sectional View on line 44 in FIG. 2. FIG. 5 is a sectional view on line 55 in FIG. 1 with the guiding jaws opened. FIG. 6 is an enlarged top view of the guiding jaws of the drill steel centralizer in FIGS. 1, 2 and 5. FIG. 7 shows, on a still larger scale, a fragmentary view of the closed jaws in FIG. 2 accommodating and guiding a drill steel. FIG. 8 is a view corresponding to FIG. 7, but showing the jaws in gripping engagement with a coupling sleeve forming part of the extension drill steel equipment in FIG. 3. FIG. 9, finally, shows on a scale corresponding to FIG. 6 a piston rod end view of one of the pistons in FIG. 5 with the guiding jaw removed.

Referring to the drawings the drill centralizer consists of :a tubular body 18 having a hollow rear extension 11 which carries a stationary clamping jaw 12 extending longitudinally of the extension 11. A bolt 13 having a nut 13 threaded thereon, extends through a transverse hole 14 in the extension 11 and the jaw 12 and carries loosely thereon a movable clamping jaw 15. The lower portion of the jaw 15 contacts the extension 11 along a longitudinal surface 16 and by screwing the nut 13 the upper portion of the movable jaw 15 may be displaced in the direction of the stationary jaw 12 for firmly gripping between the jaws 12, 15 the front end of a feed bar or shell, not

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shown, forming the usual elongated support for a reciprocable rock drill likewise not shown. Preferably the rock drill is of a type having means for reversing the drill rotation at will. The rock drill also accommodates the adapter 17 of a per se well known extension drill steel equipment, FIG. 3, also incorporating a bit 18 and one extension unit or a string of a number of extension units each consisting of a drill rod 19 carrying a screwed on coupling sleeve 20.

The upper end of the tubular body 10 carries a transverse centrally open partly cylindrical plate 21 to the opposed ends of which there are aflixed one of the elements of a pair of power cylinder and piston means, preferably as shown the cylinder housing 22 of the cylinder elements The housings 22 oppose each other and are aligned on a common axis. The cylinder housings 22 are provided at their opposed remote ends with cylinder covers 23 which are kept tightly in place axially in widened end portions of the housings 22 by means of circular retaining rings 24 inserted in ring grooves 24 FIG. 4, in said end portions. The opposite cylinder covers 25 face each other and are provided with coaxial eccentric collars 26 having bores therethrough provided on coinciding axes intersecting the drill axis of the rock dn'll on the feed bar. The collars 26 are provided with linings 27. Reciprocably arranged with a sliding fit in the cylinder housings 22 there are pistons 28 having eccentric piston rods 29 tightly journalled in and protruding through the linings 27 in the direction of each other. The throw of each piston 28 in its housing 22 is defined by the piston alternately contacting the cover 23 and the lining 27, respectively.

The faces of the pistons 28 remote from the piston rods are supplied with live pressure fluid via a conduit 30, FIG. 2, which extends along and at the outside of the plate 21 and interconnects radial bores 31, FIG. 4, in each cylinder housing 22 adjacent the cylindercover 23. A nipple 32 containing a passage 33 therein is in communication with the conduit and a conduit 34 extending through 'the body 10 and extension 11 is connected to the nipple 32. The faces of the pistons 28 adjacent the piston rods 29 are supplied with pressure fluid via a conduit 35 providing a connection between and through the cylinder covers 25, FIG. 5. The conduit 35 communicates with and carries a nipple 36 having a passage 37 therein, which leads to a conduit 38 extending through the interior of the centralizer along the conduit 34.

At a suitable convenient location remote from the drill steel centralizer there are provided control means for admitting pressure fluid to act alternately on opposed faces of the pistons 28. The control means may for example consist of a four-way valve 39 by means of which alternatively one of the conduits 34 and 38 may be connected to a pressure fluid source indicated by the arrow 40 while the other is connected to the exhaust 41.

Removably connected to the free ends of the piston rods 29 are jaws, in the example illustrated composite jaws 42 for alternatively guiding or gripping the extension drill steel equipment. Each piston rod end is provided with a bore 43 for accommodating a rear stem 44 on the jaws 42. Coaxially with the bore 43 there is provided a bore 46 of reduced diameter in a Wall portion 46 centrally in the piston rod 29. Through the bore 46' extends a bolt threadedly connected to the stem 44 and firmly pressing the stem 44 against the wall portion 46. In order to prevent rotation of the jaws 42 in the bores 43 there are provided on the outer end of the piston rods 29 opposed forwardly protruding teeth with slanting inner surface 47 which cooperate with correspondingly formed surfaces 48 on the back of the jaws 42.

Each composite jaw 42 has centrally therein a partly cylindrical middle portion 49 intended for guiding cooperation with the extension drill rods 19 and slightly larger in diameter than said rods. The middle portion 49 extends between opposed conically stepped portions 58 and 51. Outwardly of these stepped portions the jaws 42 are provided with enlarged partly cylindrical portions 52 and 53. The upper and lower portion of the enlarged portions 52 and 53 are curved outwardly providing partly cylindrical gripping surfaces 54 intended for cooperation with the coupling sleeves 20 of the drill steel equipment, FIG. 8. Each jaw 42 carries at one end thereof a lug '55 which protrude horizontally in the direction of the other cooperating jaw 42. In closed position of the jaws 42 these lugs 55. are received in notches 56 in each corresponding jaw 42.

In operation, application of pressure fluid according to FIG. 1 from the source 40 via the valve 39 and the con- 'duit 38, nipple 36 and conduit 35 will place the faces of the pistons 28 adjacent the piston rods under pressure the valve 39. For starting .a hole usually a single extension unit carrying the drill bit 18 and consisting of a single drill rod 19 and coupling sleeve 2% is screwed to the adapter 17, which is carried by the rock drill for receiving impacts and for rotation thereof in the usual manner. The bit end of the drill rod 19 to the rear of the drill bit 18 is placed on the lugs 55 of the jaws 42 in their nonguiding position. Thereupon the control valve 39 is turned to the dotted line position in FIG. 1 for reversing the connection of the conduits 38, 39 to the supply 40 and the exhaust 41, respectively. As readily seen the pressure fluid by acting on the opposed remote faces of the pistons 28 will now close the gap between the jaws 42 and bring and keep them in guiding position with their guiding portions 49 around the drill rod 19. Drilling is now commenced and the 'hole started with the bit end of the drill steel equipment firmly supported and guided.

Prior to drilling the fullfeed length the valve 39 is returned to the full line position in FIG. 1 for bringing the jaws 42 into a non-guiding position. Drilling is subsequentlyinterrupte-d .just before the forward end of the coupling sleeve 20 reaches the stepped portion 50 of the jaws 42, whereupon through turning of the valve 39 the jaws are again urged together, this time for firmly gripping and unrotatably locking the coupling sleeve 2%} by the aid of the surfaces .5 of the portions 52. Through reverse rotation of the drill the adapter 17 is now screwed out of the locked coupling sleeve 20, whereupon the drill and the adapter 17 are retracted in unison. The next extension unit consisting of a drill rod 19 and a screwed on coupling sleeve 20 are then aligned between the adapter 17 and thelocked sleeve 20, whereupon through forward feeding and normal rotation of the drill the new drill steel unit will be screwed in the locked sleeve Ztland on the adapter 17. The jaws 42 are now by means of the control valve 39 reopened to occupy non-guiding position and drilling may proceed. By thus using the jaws as a vise for locking the coupling sleeves 20 against rotation it is possible to build up in a mechanized way successively the intended full length of the extension drill steel equipment.

By reversing the order of operation it is readily seen that the extension drill steel equipment through, successive retraction from the drilled hole and successive unscrewing with simultaneous use of the jaws 42 as Vises may again be divided in its separate extension units. Such unscrewing may if necessary be assisted by manual handling if unscrewing happens to succeed only at one end of the extension unit.

When drilling in downward direction it is preferred to grip the coupling sleeves 20 by the surfaces 5415f the jaw portions 52 inwhich'case the stepped portion'fiti is-able to stop axial slipping of the gripped sleeve down into the drilled hole. During upward drilling preferably the surfaces 54 of the jaw portions 53 are used for gripping, the stepped portion 51 in a correspondingmanner acting as an axial stop to prevent slipping of the drill string rearwardly out of the closed jaws 42. I

In the disclosed centralizer the vise action of the jaws is efliciently augmented by the direct application of power from the pistons 28 via the piston rods 29 on thejaws 42 and the rigidity of these elements. Also there is full rigidity of the jaws 42 against rotation thanks to the eccentric mounting of the piston rods 29 in the housings. 22, which prevents such rotation.

The embodiment of the invention above described and illustrated in the drawings should only be considered as an example and the invention may be modified in several ways within the scope of the following claims.

What I claim is:

1. In pressure fluid operated drill steel centralizer apparatus of the character described for mounting on the feed shell of a rock drill and having a support therefor and a source of pressure fluid, the combination which comprises a pair of opposed, cooperating gripping jaws movably disposed on said support for movement thereon from a gripping position adjacent each other to a separated position away from each other, guide surfaces disposed on the opposed portions of said jaws for forming in the said gripping position thereof a guide opening for drill rods passing therethrough having a diameter larger than said drill rods, gripping surfaces disposed on the opposed portions of said jaws adjacent said guide surfaces and forming in the said gripping positionof said jaws a gripper opening larger than said guide openings for positively grasping a drill rod coupling sleeve therein, pressure fluid operated power cylinder and piston means disposed on said support and connected to said jaws and in flow communication with said source for moving said jaws to said gripping position, and holding them in that position, and means for moving said jaws to saidseparated position.

2. In pressure fluid operated drill steel centralizer apparatus of the character described for mounting on the feed shell of a rock drill and having a support therefor and a source of pressure fluid, the combination which comprises a pair of opposed, axially aligned gripping jaws movably disposed on said support for movement from a gripping position adjacent each other to a separated position away from each other, guide surfaces disposed on the opposed portions of said jaws forming in the said gripping position thereof a guide opening for drill rods passing therethrough having a diameter larger than said drill rods, gripping surfaces disposed on the opposed portions of said jaws adjacent said guide surfaces and forming in the gripping position of said jaws a gripper opening larger than said guide opening for positively grasping a drill rod coupling sleeve therein, a separate pressure fluid operated power cylinder and piston connected to each of said jaws and disposed on said support and in flow communication with said source for moving said jaws to said gripping position and holding them in that position and for moving said jaws from said gripping position to said separated position, and control means disposed between said source and said power cylinders for selecting the position of said jaws and for holding the said jaws in the said selected positions.

3. Apparatus as described in claim 2 in whicheach said piston includes a piston rod projecting therefrom with said piston rods being axially aligned and in opposed relation to each other and having said opposed jaws disposed thereon on the ends opposite said piston, and means disposed in each of said cylinders and connected to said rods for preventing rotation of said rods in said cylinders.

4. Apparatus as described in claim 3 in which said rotation preventing means is a journal receiving said piston rods in each, of said cylinders, with said journals being disposed with the axes thereof in parallel relationship to an axis of the said respective cylinder but radially offset therefrom.

5. Apparatus as described in claim 2 in which a pair of partly cylindrical gripping surfaces is provided on the opposed surfaces of each of said jaws adjacent each side of the said guide surface thereon.

6. In pressure fluid operated drill steel centralizer apparatus of the character described for mounting on the feed shell of a rock drill and having a support therefor and a source of pressure fluid, the combination which comprises a pair of opposed, axially aligned gripping jaws movably disposed on said support for movement from a gripping position adjacent each other to a separated position away from each other, guide surfaces disposed on the opposed portions of said jaws forming in the said gripping position thereof a guide opening for drill rods passing therethrough having a diameter larger than said drill rods, a pair of pressure fluid operated power cylinder and piston means disposed on said support and connected to said jaws and in flow communication with said source for moving said jaws from said separated position to said gripping position and vice versa and for supplying the sole means of supporting and gripping action of said jaws, and control means disposed between said source and both said power cylinder and piston means for selectively admitting pressure fluid to said piston and cylinder means for said gripping and separated positions thereof and for holding said jaws in said selected positions.

7. In pressure fluid operated drill steel centralizer apparatus of the character described for mounting on the feed shell of a rock drill and having a support therefor and a source of pressure fluid, the combination which comprises a pair of opposed, axially aligned pressure fluid actuated power cylinder and piston means on said support, a pair of cooperating relatively movable gripping jaws with one each of said pair disposed on each of said power cylinder and said piston means for movement from a gripping position adjacent each other to a separated position away from each other, guide surfaces disposed on the opposed portions of said jaws forming in the said gripping position thereof a guide opening for drill rods passing therethrough having a diameter larger than said drill rods, gripping surfaces disposed on the opposed portions of said jaws adjacent said guide surfaces and forming in the said gripping position of said jaws a gripper opening larger than said guide opening for positively grasping a drill rod coupling sleeve therein, and control means disposed between the said source and the said pair of pressure fluid actuated power cylinder and piston means for selectively admitting pressure fluid thereto for moving said jaws from said gripping position to said separated position and vice versa and for holding said jaws in said selected position.

8. A drill steel gripper to be mounted on the feed shell of a rock drill for intermittently gripping portions of the drill string actuated by said rock drill and having a support therefor for mounting on said feed shell and a source of pressure fluid, the combination which comprises a pair of opposed power cylinders aligned axially on said support, a piston reciprocably movable in each said cylinder, piston rods connected to each said piston and projecting from said cylinders in a direction opposing each other, a pair of opposed gripping jaws with each of said pair connected to a dilferent one of said piston rods by securing means passing through one end of the piston rod into the back of each of the jaws and freely and solely supported thereby for movement by said pistons respectively from a gripping position adjacent each other to a separated position away from each other, grip ping surfaces on said jaws for frictionally gripping predetermined portions of said drill string in said gripping position of said jaws, and control means between said source and said cylinders for admitting pressure fluid selectively against the faces of said pistons remote from said piston rods for moving said jaws into said gripping position, and against the opposite faces of said piston for moving said jaws into said separated position and for holding said jaws in said selected positions, and means for preventing relative rotation between said piston rods and said cylinders.

9. A drill steel gripper as recited in claim 8 in which said rotation preventing means is a journal disposed in each of said cylinders slidably receiving said piston rods, with the axis of each said journal being radially ofiset from but parallel with the axis of its respective cylinder.

10. In drill steel gripper apparatus of the character described for mounting on the feed shell of a rock drill for intermittently gripping portions of a drill string and for preventing loss of the drill string during coupling and uncoupling operations and having a support for mounting on said feed shell, the combination which comprises a pair of opposed, axially aligned gripping jaws movably disposed on said support for movement from a gripping position adjacent each other to a separated position away from each other, guide surfaces disposed on the opposed portions of said jaws forming in the gripping position thereof a guide opening for drill rods passing therethrough having a diameter larger than said drill rods but smaller than the coupling sleeve holding said drill rods together, gripping surfaces disposed on the opposed portions of said jaws adjacent said guide sur faces and forming in the said gripping position of said jaws =a gripper opening having a diameter larger than said guide opening for positively grasping a drill rod coupling sleeve therein, a tapered portion disposed on the opposed portions of said jaws between said guide surfaces and said gripping surfaces and inclined away fiom the axis of said jaws, said tapered surfaces forming abutments for catching and engaging said drill sleeve for preventing loss of said drill string during coupling and uncoupling operations, means for moving said jaws from said gripping position to said separated position and vice versa, and control means for selecting the positions of said jaws and for holding said jaws in said selected position.

References Cited by the Examiner UNITED STATES PATENTS 2,242,739 5/ 1941 Anderson 74841 2,679,177 5/1954 Gepfert 26935 2,75 9,679 8/ 6 Torregrossa 3 08-4 DON A. WAITE, Primary Examiner.

FRANK SUSKO, Examiner. 

2. IN PRESSURE FLUID OPERATED DRILL STEEL CENTRALIZER APPARATUS OF THE CHARACTER DESCRIBED FOR MOUNTING ON THE FEED SHELL OF A ROCK DRILL AND HAVING A SUPPORT THEREFOR AND A SOURCE OF PRESSURE FLUID, THE COMBINATION WHICH COMPRISES A PAIR OF OPPOSED, AXIALLY ALIGNED GRIPPING JAWS MOVABLY DISPOSED ON SAID SUPPORT FOR MOVEMENT FROM A GRIPPING POSITION ADJACENT EACH OTHER TO A SEPARATED POSITION AWAY FROM EACH OTHER, GUIDE SURFACES DISPOSED ON THE OPPOSED PORTIONS OF SAID JAWS FORMING IN THE SAID GRIPPING POSITION THEREOF A GUIDE OPENING FOR DRILL RODS PASSING THERETHROUGH HAVING A DIAMETER LARGER THAN SAID DRILL RODS, GRIPPING SURFACES DISPOSED ON THE OPPOSED PORTIONS OF THE JAWS ADJACENT SAID GUIDE SURFACES AND FORMING IN THE GRIPPING POSITION OF SAID JAWS A GRIPPER OPENING LARGER THAN SAID GUIDE OPENING FOR POSITIVELY GRASPING A DRILL ROD COUPLING SLEEVE THEREIN, A SEPARATE PRESSURE FLUID OPERATED POWER CYLINDER AND PISTON CONNECTED TO EACH OF SAID JAWS AND DISPOSED ON SAID SUPPORT AND IN FLOW COMMUNICATION WITH SAID SOURCE FOR MOVING SAID JAWS TO SAID GRIPPING POSITION AND HOLDING THEM IN THAT POSITION AND FOR MOVING SAID JAWS FROM SAID GRIPPING POSITION TO SAID SEPARATED POSITION, AND CONTROL MEANS DISPOSED BETWEEN SAID SOURCE AND SAID POWER CYLINDERS FOR SELECTING THE POSITION OF SAID JAWS AND FOR HOLDING THE SAID JAWS IN THE SAID SELECTED POSITIONS. 